I first met with the CTO in a one-to-one interview at the office. He asked me questions about my experience and presented me the company, the future outlook, the new processes they are putting in place and how & where I would fit in.
The second interview was with the CPO. He went more into details about the role of a Product Owner, the team, how I would work with Business Owners, etc.
Both the CTO & CPO made sure the role & responsabilities were clear to me and they wanted to make sure I wouldn't get bored in the role, because I came from a smaller company where I had to do a lot of things (PO, UX research, testing, scrum master...!), which I really appreciated.
In other words, they made sure I was a good fit for them but that I was also sure they were a good fit for me!